Coal can only stare at the demon. The creature continues to bend and twist his body, testing his immense form, his tail whipping around and curling along his leg. A smirk rises to his face as he continues to move his hands across himself, fingers tracing his veins, body pumping with infernal strength and power.
On some level, Coal knows the risks involved. He's creating a demon - a creature that every tome and teacher warned about, and that might betray him. But... Somehow, this was Xanadar. This was the small imp he had always known, ever since he had begun his study of magic. And though the lesser demon was now powerful enough to shrug off the basic binding that made him a familiar, he remained. Why? Was he just interested in more power? Or was there more?
"Master?" Coal twitches at the word, gasping as Xan's form pushes up against him, his flesh heating the human the moment they touch. "What are you thinking about?"
Coal's face burns as red as Xanadar's skin. His words fumble for a few moments, but then they find purchase. "About... going further. Do you... Do you want to see how powerful you can get?" It was a mistake. He knows it's a mistake, but he can't resist making that mistake.
Xan's eyes lurch, and the demon nods, the grin on his face spreading even wider. "Ooooh, yes, master. With you, ascension isn't just a dream. I'll be a full demon. Perhaps even a demon lord. But to start... You need to be in the mood, don't you?"
His mouth meets Coal's, the demon's wicked tongue snaking its way in. Coal struggles for breath as a couple of thick arms make their way around him, forcing him back against the wall. The former imp's tongue wraps around the human's, pushing into his throat, the human's throat parched by the demon's infernal fluid. But every moment of the kiss drives more desire through both of them, their bodies at attention, their shafts both rising upwards, meeting and pressing against each others' abdominals, dripping with pre.
The kiss breaks, and while Coal's mind continues reeling, Xanadar steps back, his tail twisting back around, jerking and teasing at his length. The demon moans as his shaft rises at the touch, far larger than anything should be, even for a creature of Xan's size. Over twenty-five inches of pure, virile, demonic flesh rise up, and as the demon continues to pump at himself, it only rises higher and higher. Coal's hands move down to start teasing himself, both hands working at his own impressive length, his shaft barely meeting Xan's disproportionately large tool.
Even as the demon continues to prepare himself, his body rises off the ground. His body and shaft pushes up higher and higher, veins pumping with every moment, thick arms and sturdy legs moving to embrace Coal as he continues to rise. His shaft continues to drip, even as his body rises high enough to push against Coal's mouth. The human gasps, before an impossible amount of flesh slips right in.
"Xan, what's... Mmmph!" With his mouth stuffed, Coal can only mumble. But every sound he makes, every muffled noise, only resounds through the demon's shaft, coaxing more and more excitement through the creature's body.
"You're nervous, Master. I can tell. You're afraid I'll outgrow you... Overpower you... Drag you into the abyss." His arms grasp Coal's shoulders, his shaft starting to force their way against his throat. "But I know how to prove I won't. There'll be no need to worry about me if you're much stronger than me, right?"
Coal gasps as Xanadar begins to thrust. It should be impossible for the first foot of Xan's rock-hard shaft to push right into his throat, but the demon's anatomy, ability, or magic... SOMETHING is making the impossible act possible, making it so Coal can take, has to take every inch, every foot of the demon's length right into his throat.
"So, this time, you can grow first." The demon's smile sends a shiver of hesitation down Coal's body. Every bit of the demon's shaft pulses as it fits into Coal's mouth, his hole completely plugged as the demon braces himself. The slightest groans and moans escape Xan's lips, but as Coal grasps Xan's legs, the demon lets loose.
Coal thought he was ready for it. He had spent so much time draining his own, demonic seed. And then, right after Xan's transformation, he had tasted the demon's seed, it enough to send him soaring upwards and outwards, pushing his head towards the ceiling, pushing his body beyond any hope of normalcy. But this time, the load flows through even faster, tastes even muskier, spreads through him with a vigor beyond what he remembered.
Coal's limbs buckle, even as more and more mass packed onto every inch. His two-foot cock bobs and drips as it continues to inch higher and further. His growth itself pushes Xan's body and legs away, his pecs forcing the demon upwards. Even as his hands cracked the wall and as his feet dug into the ground, all feeling in his limbs left. A half-ton of weight slams into the ground as Coal falls to his knees, but as he lurches, his head rises higher and higher, soon just as tall in his new stance, more mass driving his legs into the ground, thicker arms hanging down and firmer hands grasping at his own desperate shaft.
As the last drops escape, Xan pulls out, hovering at eye level with Coal. The human clutches his chest and gasps for breath, his body heaving with effort. Every motion is an effort, his impressive strength necessary to move those overwhelming limbs. Every turn and nudge sends every fiber of his body on alert, and every slight move turns into a flex. "H-how... That was even better than before, but..."
As he falls from the high of Xan's load, his own painful crotch jerks at his mind. Despite the overwhelming pleasure, that overpowering growth, the flood of hormones now coursing through his body, his shaft remained on edge, dripping enough pre to fill a cup but refusing to go any further. Both thick hands grasp around to handle the length, but though insane pleasure courses through his cock, it doesn't force him to blow.
Xanadar winks as his head and body moves, his six-foot body reaching down to embrace the shaft that now matches half of his size. "Sex made me into this, Master. And because of that, I understand sex better than most demons. That means I know how to keep you on edge." His tail slips around, dragging right up Coal's shaft, every moment forcing the human's oversized balls to surge and tense further, the pressure continuing to build. "After all, I wouldn't want you to miss a single moment of the most intense pleasure you've ever experienced. And I wouldn't want to waste any of this."
In one swift motion, the demon's mouth wraps around the tip of Coal's shaft. His arms hug and squeeze, tugging and pulling at that length. The moment he starts, the moment his mouth drains Coal's first few drops, the human's world goes white, pleasure beyond any flowing into his mind as his seed flows out.
There's no way for him to comprehend what goes on. All he knows is pleasure as Xanadar milks him and drains him. Somewhere in his mind, he's aware that he's nudging against more and more flesh. That that thick limb pushing against him is Xan's cock. That that flapping is Xan's new wings. That those biceps pressing against him are Xan's. That eventually, something pulls off of his mouth. That instead, a thick bulk is completely wrapping around him.
He's not sure how long it takes, but the pleasure eventually fades. But he's not ready to see what meets him.